I use it as an individual. As such, I receive their newsletter. The most recent one was sent today, and it suggests that people use RebelMouse to showcase their summer photos.
To do it, you will need to create a new sub-page in RebelMouse for your photos. Next, connect your Instagram, Flickr, or a photo RSS feed to it (through the Content & Feeds tab). There is also a way to add other photos to your RebelMouse by dragging them in.
I thought this was interesting for a couple of reasons. One, it appears that RebelMouse wants to get people thinking about using it as their primary way to show other people the photos that they took for a specific event. (Instead of Flickr, Instagram, your Facebook page, or your personal blog). I had not considered this possibility before I read their newsletter.
Two, it looks as though you can add things to your RebelMouse page that are not from the website that you sign into RebelMouse with. For example, you can sign in via Facebook, Twitter, or Google +. You can’t sign in through Flickr, but you can have RebelMouse put your Flickr photos onto your RebelMouse page.